linux-kernel - [RFC PATCH 6/6] perf bpf: Generate bpf prologue for arguments

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 5 May 2015 10:10:12 +0000
From:	He Kuang <hekuang@...wei.com>
To:	<ast@...mgrid.com>, <davem@...emloft.net>, <acme@...nel.org>,
	<mingo@...hat.com>, <a.p.zijlstra@...llo.nl>,
	<masami.hiramatsu.pt@...achi.com>, <jolsa@...nel.org>
CC:	<wangnan0@...wei.com>, <lizefan@...nel.org>,
	<linux-kernel@...r.kernel.org>, <pi3orama@....com>
Subject: [RFC PATCH 6/6] perf bpf: Generate bpf prologue for arguments

Generate bpf prologue before attaching bpf progs to perf probe event. If
prologue is generated, it will be pasted in front of the original bpf
prog.

Signed-off-by: He Kuang <hekuang@...wei.com>
---
 tools/perf/util/bpf-loader.c | 66 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)

diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index c646ca4..8c746ef 100644
--- a/tools/perf/util/bpf-loader.c
+++ b/tools/perf/util/bpf-loader.c
@@ -900,6 +900,69 @@ bpf_perf_prog_load(struct bpf_obj *obj, struct bpf_perf_prog *prog)
 	return 0;
 }
 
+#ifdef HAVE_DWARF_SUPPORT
+#if 0
+static void show_bpf_insn(char *buf, int len)
+{
+	int i, j;
+	char *ptr = buf;
+
+	for (i = 0; i < len; i++) {
+		pr_debug("[%03d] ", i);
+		for (j = 0; j < 8; j++)
+			pr_debug("0x%02x, ", (*ptr++) & 0xff);
+		pr_debug("\\\n");
+	}
+}
+#endif
+
+static int bpf_obj_prologue(struct bpf_obj *obj)
+{
+	struct bpf_perf_prog *prog;
+	int ret = -1;
+
+	list_for_each_entry(prog, &obj->progs_list, list) {
+		int count;
+		char *result;
+		int new_count;
+
+		if (!prog->pev)
+			continue;
+
+		ret = get_bpf_prologue(prog->pev, &result, &count);
+		if (ret)
+			return ret;
+
+		if (count > 0) {
+			bpf_dump_prog((struct bpf_insn *)result, count);
+
+			new_count = prog->insns_cnt + count;
+			result = realloc(result,
+					new_count * sizeof(struct bpf_insn));
+			if (!result)
+				return -ENOMEM;
+
+			memcpy(result + count * sizeof(struct bpf_insn),
+				prog->insns,
+				prog->insns_cnt * sizeof(struct bpf_insn));
+
+			free(prog->insns);
+			prog->insns = (struct bpf_insn *)result;
+			prog->insns_cnt = new_count;
+		} else {
+			pr_debug("bpf: no prologue generated\n");
+		}
+	}
+
+	return ret;
+}
+#else
+static int bpf_progs_prologue(struct bpf_obj *obj __maybe_unused)
+{
+	return 0;
+}
+#endif
+
 static int
 bpf_obj_load_progs(struct bpf_obj *obj)
 {
@@ -946,6 +1009,9 @@ int bpf__load(const char *path)
 		goto out;
 	if ((err = bpf_obj_relocate(obj)))
 		goto out;
+	err = bpf_obj_prologue(obj);
+	if (err)
+		goto out;
 	if ((err = bpf_obj_load_progs(obj)))
 		goto out;
 
-- 
1.8.5.2

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/